Method and system for detecting an elevated object situated within a parking facility

ABSTRACT

A method for detecting an elevated object situated within a parking facility, using at least two video cameras that are spatially distributed within the parking facility and whose visual ranges overlap in an overlap area. The method encompasses the following: recording particular video images of the overlap area with the aid of the video cameras; analyzing the recorded video images in order to detect an elevated object in the recorded video images, and ascertaining, based on the recorded video images, whether in the detection of an elevated object the detected elevated object is real. A corresponding system, a parking facility, and a computer program are also provided.

FIELD

The present invention relates to a method for detecting an elevatedobject situated within a parking facility, for example a parking deck,in particular within a driving path of a parking facility. Moreover, thepresent invention relates to a system for detecting an elevated objectsituated within a parking facility, for example a parking deck, inparticular within a driving path of a parking facility. Moreover, thepresent invention relates to a parking facility. Furthermore, thepresent invention relates to a computer program.

BACKGROUND INFORMATION

German Patent Application No. DE 10 2015 201 209 A1 describes a valetparking system for automatically bringing a vehicle from a handover zoneto an assigned parking space within a predefined parking area. Theconventional system encompasses a parking facility monitoring systemwith at least one stationary sensor unit. The parking facilitymonitoring system is designed to locate the vehicles traveling withinthe predefined parking area.

SUMMARY

An object of the present invention is to provide for efficientlydetecting an elevated object situated within a parking facility, forexample a parking deck, in particular within a driving path of a parkingfacility.

This object may be achieved via the present invention.

Advantageous embodiments of the present invention are described herein.

According to one aspect of the present invention, a method for detectingan elevated object situated within a parking facility, using at leasttwo video cameras that are spatially distributed within the parkingfacility and whose visual ranges overlap in an overlap area, isprovided, including the following steps:

-   a) recording particular video images of the overlap area with the    aid of the video cameras,-   b) analyzing the recorded video images in order to detect an    elevated object in the recorded video images,-   c) ascertaining, based on the recorded video images, whether in the    detection of an elevated object the detected elevated object is    real.

According to another aspect of the present invention, a system fordetecting an elevated object situated within a parking facility isprovided, the system being designed for carrying out the method fordetecting an elevated object situated within a parking facility.

According to another aspect of the present invention, a parking facilityis provided that encompasses the system for detecting an elevated objectsituated within a parking facility.

According to yet another aspect of the present invention, a computerprogram is provided that includes program code for carrying out themethod for detecting an elevated object situated within a parkingfacility, when the computer program is executed on a computer.

The present invention is based on the finding that the above object maybe achieved by checking, based on video images recorded in chronologicalsuccession, whether or not an initially detected elevated object isreal. This means in particular that a result that has been ascertainedbased on the initially recorded video images (the result indicating thatan elevated object has been detected) is verified or checked by trackingthe initially detected object over time. In particular, the initiallydetected object may thus be efficiently checked for plausibility. Thisis because it is generally not possible, for example, for an object tosuddenly disappear. The object, provided that it is actually real,should be detected also during an analysis of video images that havebeen recorded subsequent to the video image in which the object wasinitially detected, and at that location should have, for example, thesame properties as before.

This means in particular that, based on particular evaluations of videoimages that are recorded in each case in chronological succession, it ischecked whether a recognized, i.e., detected, object is real, i.e.,whether the object is even possible or realistic.

This yields the technical advantage, for example, that false alarms maybe reduced or avoided, which advantageously allows efficient operationof the parking facility, and for example, efficient operation ofdriverless motor vehicles traveling within the parking facility.

This yields the technical advantage, for example, that objects may beefficiently recognized so that a collision with such objects may beprevented.

This yields the technical advantage that a concept for efficientlydetecting an elevated object situated within a parking facility may beprovided.

According to one specific embodiment of the present invention, it isprovided that for detecting an elevated object in the recorded videoimages, the following steps are provided according to the analysisaccording to step b):

-   -   rectifying the recorded video images,    -   comparing the particular rectified video images to one another        in order to recognize a difference in the recorded overlap        areas,    -   detecting an elevated object based on the comparison.

Prior to a comparison of the video images, it is provided in particularthat the video images are transformed, i.e., rectified. The rectifiedvideo images are then compared to one another.

When all rectified video images of the overlap area show no differences,for example, i.e., are the same or identical, or differ maximally by apredetermined tolerance value, it may be assumed that no elevated objectis situated on the particular visual axis between the overlap area andthe video cameras. In this regard, no elevated object is detected. Thus,in particular a result is ascertained which indicates that no elevatedobject has been detected.

However, if an elevated object is situated on a visual axis between theoverlap area and one of the video cameras, this one video camera doesnot have the same view as the other video cameras. The rectified videoimage in question will thus differ from the rectified video image of theother video cameras by an amount that is greater than the predeterminedtolerance value. In this regard, an elevated object is then detected.Thus, in particular a result is ascertained which indicates that anelevated object has been detected.

An elevated object may thus be efficiently detected with the aid of theat least two video cameras.

Within the meaning of the description, a parking facility is inparticular a parking facility for motor vehicles. The parking facilityis a parking deck or a parking garage, for example. An object to bedetected is situated, for example, within a driving path of the parkingfacility.

An elevated object refers in particular to an object whose heightrelative to a floor of the parking facility is at least 10 cm.

The elevated object is situated, for example, on a floor of the parkingfacility, for example on a driving surface or within a travel area, forexample within a driving path, of the parking facility. The elevatedobject is thus situated, for example, within a driving path of theparking facility.

A rectification of the recorded video images in particular encompassesor is, for example, a transformation of the recorded video images intothe bird's-eye view. This means in particular that the recorded videoimages are transformed into the bird's-eye view, for example. Thesubsequent comparison may thus be advantageously carried out in aparticularly efficient manner.

Within the meaning of this description, the phrases “same imageinformation” and “identical image information”, or “same video images”and “identical video images”, in particular also encompass the case thatthe pieces of image information or the video images have a maximumdifference that is within a predetermined tolerance value. Onlydifferences that are greater than the predetermined tolerance valueresult in a detection of an object. This means in particular that smalldifferences in the brightness information and/or color information areallowed in order to draw the conclusion that the pieces of imageinformation or the video images are the same or identical, provided thatthe differences are less than the predetermined tolerance value.

This means in particular that, for example, an elevated object isdetected only when, for example, the video images differ by an amountthat is greater than the predetermined tolerance value. This means inparticular that an elevated object is detected only when, for example,one overlap area differs from the other overlap areas by an amount thatis greater than the predetermined tolerance value.

In one specific embodiment, it is provided that step c) encompassesascertaining an object speed, the ascertained object speed beingcompared to a predetermined object speed threshold value, and based onthe comparison it being determined whether the detected elevated objectis real.

This yields the technical advantage, for example, that it may beefficiently determined whether the detected elevated object is real.This is because certain speeds are generally expected for real objectswithin a parking facility. For example, an object speed of 150 km/h isnot plausible. In this case, the detected object is not real.

This means in particular that it is determined that the detectedelevated object is real when the ascertained object speed is less thanor less than or equal to the predetermined object speed threshold value,it being determined that the detected elevated object is not real whenthe ascertained object speed is greater than or greater than or equal tothe predetermined object speed threshold value.

An object speed threshold value is, for example, 60 km/h, for example 50km/h, in particular 40 km/h.

This specific embodiment is thus based on the finding that objectswithin the parking facility are generally able to move only at a certainmaximum speed.

According to one specific embodiment, it is provided that step c)encompasses ascertaining a movement of the detected elevated object, itbeing ascertained whether the movement of the detected elevated objectis plausible, and based on the plausibility check it being determinedwhether the detected elevated object is real.

This yields the technical advantage, for example, that it may beefficiently determined whether the detected elevated object is real.This is because certain movements are generally expected for realobjects within a parking facility. Objects in the size range of a motorvehicle cannot move vertically upward or change their direction by 90°on the spot. Such conclusions cannot be drawn for smaller objects,since, for example, people can jump into the air. Ascertaining theplausibility of the movement is carried out, for example, as a functionof the size of the detected object. Objects within the size range of amotor vehicle are subject, for example, to the above-describedlimitations in movement.

In one specific embodiment, step c) encompasses ascertaining whether,and if so, at which location in the video images, the detected elevatedobject moves into the particular video image and/or moves out of theparticular video image. In particular, it is determined that thedetected elevated object is real when the detected object moves into theparticular video image at the edge as the location, and/or moves out ofthe particular video image at the edge as the location. In particular,it is determined that the detected elevated object is not real when thedetected object appears within the video image or disappears within thevideo image without having crossed the edge of the video image.

This specific embodiment is based on the finding that elevated objectscan move into a scene (in the present case, the video images) onlyacross the edge of the scene, and/or can leave the scene again onlyacross the edge. In the middle of a scene, i.e., within the scene, anobject cannot simply appear or emerge and/or disappear.

This yields the technical advantage, for example, that it may beefficiently determined whether the detected elevated object is real.

According to one specific embodiment, it is provided that step c)encompasses classifying the detected elevated object, it beingdetermined, based on the classification, whether the detected elevatedobject is real.

This yields the technical advantage, for example, that it may beefficiently determined whether the detected elevated object is real.This is because generally only certain objects are expected within aparking facility. In addition, the knowledge of the type of object maybe efficiently utilized for determining whether the detected object isreal.

Step c) encompasses, for example, checking whether the classificationchanges over time, the determination of whether the object is real beingcarried out based on this check. It is determined that the object is notreal in particular when a change is ascertained. It is determined thatthe object is real in particular when no change is ascertained.

The classification encompasses, for example, ascertaining a size, inparticular a length and/or a height and/or a width, of the detectedobject.

According to one specific embodiment, it is provided that step c)encompasses ascertaining a dynamic property of the detected object, theascertained dynamic property of the detected object being compared to apredetermined reference value, and it being determined, based on thecomparison, whether the detected elevated object is real.

This yields the technical advantage, for example, that it may beefficiently determined whether the detected elevated object is real,since common objects within a parking facility generally have certaindynamic properties.

Examples of a dynamic property are a speed, an acceleration, and amovement direction.

For example, multiple dynamic properties are ascertained in each case.Statements made in conjunction with one dynamic property similarly applyfor multiple dynamic properties, and vice versa.

In one specific embodiment, it is provided that, based on theclassification, an object-specific speed threshold value is predefinedas the object speed threshold value for the comparison.

This yields the technical advantage, for example, that the determinationof whether the detected object is real may be carried out for a specificobject.

In one specific embodiment, it is provided that, based on theclassification, an object-specific reference value is predefined for thecomparison with the ascertained dynamic property.

This yields the technical advantage, for example, that the determinationof whether the detected object is real may be carried out for a specificobject.

In one specific embodiment, it is provided that it is ascertainedwhether the ascertained movement is plausible for the classified object.

This yields the technical advantage, for example, that the determinationof whether the detected object is real may be carried out for a specificobject.

This specific embodiment is based on the finding that different objectsmove differently. A person generally moves differently than a motorvehicle. For example, a person can turn on the spot, which is generallynot possible for a motor vehicle. Thus, persons have, for example,different movement profiles than motor vehicles.

With this knowledge, it may thus be advantageously and efficientlychecked whether the ascertained movement during detection of an elevatedobject in video images that are recorded in chronological succession maystill be associated with the same type of object.

An elevated object cannot be a motor vehicle one time and a pedestrianat a later time.

A detected elevated object is classified, for example, in one of thefollowing classes of object types: motor vehicle, pedestrian, cyclist,animal, baby stroller, other.

In one specific embodiment, it is provided that when the detectedelevated object is not real, one or more of the following actions is/arecontrolled: stopping all driverless motor vehicles traveling within theparking facility, summoning a service person to the video cameras,carrying out a function check of the video cameras, adjusting aparticular setpoint trajectory to be driven along by driverless motorvehicles traveling within the parking facility, in order to bypass asection of the parking facility that encompasses the overlap area,blocking a section of the parking facility that encompasses the overlaparea, blocking a story of the parking facility that encompasses theoverlap area, transmitting an error message to an operator via acommunications network.

This yields the technical advantage, for example, that safety for theparking facility may be efficiently enhanced.

According to one specific embodiment, it is provided that at least nvideo cameras are used, where n is greater than or equal to 3, an objectbeing detected when, based on the comparison, it is ascertained that oneoverlap area already differs from the other recorded overlap areas, orthat at least m overlap areas differ from the other overlap areas, wherem is greater than 1 and less than n, or that all n overlap areas differfrom one another. The more cameras that are used and the more overlapareas that are to differ, the more accurately the concept according tothe present invention, i.e., in particular the method according to thepresent invention, may demarcate the “footprint” of the elevated object.

According to one specific embodiment, it is provided that the overlaparea relative to at least one video camera is illuminated differentlycompared to the other video cameras.

This yields the technical advantage, for example, that an object may beefficiently detected. This is due to the fact that if one side of theobject is illuminated preferentially or differently than other sides ofthe object, differences in the recorded video images may be recognizedin a particularly easy and efficient manner.

That the overlap area relative to at least one video camera isilluminated differently compared to the other video camera means, forexample, that a light source that illuminates the overlap area from thedirection of the at least one video camera is situated within theparking facility. There is no illumination from the directions of theother video cameras, for example; i.e., no additional light sources areprovided, or different illuminations are provided, for example lightsources that are operated at different light intensities.

According to one specific embodiment, it is provided that the overlaparea encompasses a travel area for motor vehicles.

This yields the technical advantage, for example, that the travel areamay be efficiently monitored.

According to one specific embodiment, it is provided that the comparisonencompasses comparing a particular brightness of the rectified videoimages in order to recognize differences in brightness as a difference.

This yields in particular the technical advantage that differences inthe recorded overlap areas may be efficiently recognized.

According to one specific embodiment, it is provided that the parkingfacility is configured or designed for executing or carrying out themethod for detecting an elevated object situated within a parkingfacility.

According to one specific embodiment, it is provided that the method fordetecting an elevated object situated within a parking facility isexecuted or carried out with the aid of the system for detecting anelevated object situated within a parking facility.

Technical functionalities of the system result analogously fromcorresponding technical functionalities of the method, and vice versa.

This means in particular that system features result from correspondingmethod features, and vice versa.

According to one specific embodiment, it is provided that at least nvideo cameras are provided, where n is greater than or equal to 3.

According to one specific embodiment, it is provided that one ormultiple or all of the following steps is/are carried out with the aidof a data processing device: step b), step c), ascertaining a result ofwhether an elevated object has been detected in the recorded videoimages, detecting an elevated object in the recorded video images,determining whether the detected elevated object is real, rectifying therecorded video images, comparing the particular rectified video imagesto one another to recognize a difference in the recorded overlap areas,detecting an elevated object based on the comparison. This means inparticular that according to one specific embodiment, a data processingdevice is provided that is designed for carrying out one or multiple orall of the steps described above.

The data processing device includes, for example, one or multipleprocessors that are encompassed, for example, by at least one of thefollowing elements: video camera or video cameras and/or a processingunit that is different from the video cameras.

In one specific embodiment, it is provided that at least one of theabove steps carried out in conjunction with the data processing deviceis carried out with the aid of at least one of the video cameras and/orwith the aid of a processing unit that is different from the videocameras.

This yields the technical advantage, for example, that redundancy isefficiently provided by the processing unit. When the video cameracarries out the steps in question, this yields the technical advantage,for example, that the video camera is efficiently utilized.

According to one specific embodiment, an illumination device isprovided. The illumination device is designed for illuminating theoverlap area relative to at least one video camera differently comparedto the other video cameras.

The illumination device encompasses, for example, one or multiple lightsources that are spatially distributed within the parking facility. Thelight sources are situated in such a way, for example, that the overlaparea is illuminated differently from different directions.

In one specific embodiment, it is provided that the overlap area isilluminated in the manner of a spotlight from a preferred direction, forexample with the aid of the illumination device.

In one specific embodiment, it is provided that the overlap area isilluminated from a single direction.

The light sources are situated, for example, on a ceiling and/or on apillar and/or on a wall, generally on an infrastructure element of theparking facility.

According to one specific embodiment, it is provided that at least nvideo cameras are used, where n is greater than or equal to 3.

According to one specific embodiment, it is provided that a particularoverlap area is monitored by exactly three or exactly four videocameras, whose visual ranges overlap in the particular overlap area.

In one specific embodiment, it is provided that multiple video camerasare provided, whose visual ranges overlap in an overlap area. This meansin particular that multiple overlap areas are detected, in particularmonitored, here with the aid of multiple video cameras.

The phrase “respective” encompasses in particular the phrase “and/or.”

“Not real” means unreal.

According to one specific embodiment, it is provided that one ormultiple or all video cameras is/are situated at a height of at least 2m, in particular 2.5 m, relative to a floor of the parking facility.

This yields the technical advantage, for example, that the overlap areamay be efficiently recorded.

The present invention is explained in greater detail below withreference to preferred exemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flow chart of a method for detecting an elevated objectsituated within a parking facility.

FIG. 2 shows a system for detecting an elevated object situated within aparking facility.

FIG. 3 shows a parking facility.

FIG. 4 shows two video cameras that monitor a floor of a parkingfacility.

FIG. 5 shows the two video cameras of FIG. 4 during the detection of anelevated object.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

The same reference numerals may be used for identical features in thefollowing discussion.

FIG. 1 shows a flow chart of a method for detecting an elevated objectsituated within a parking facility, using at least two video camerasthat are spatially distributed within the parking facility, and whosevisual ranges overlap in an overlap area.

The method encompasses the following steps:

-   -   recording 101 particular video images of the overlap area with        the aid of the video cameras,    -   analyzing 103 the recorded video images in order to detect an        elevated object in the recorded video images,    -   ascertaining 105, based on the recorded video images, whether in        the detection of an elevated object the detected elevated object        is real.

Step 103 and/or step 105 encompass(es), for example, the followingsteps:

-   -   rectifying the recorded video images,    -   comparing the particular rectified video images to one another        in order to recognize a difference in the recorded overlap        areas,    -   detecting an elevated object based on the comparison.

The step of rectifying encompasses in particular transforming therecorded video images into the bird's-eye view. This yields inparticular the technical advantage that the video images maysubsequently be efficiently compared.

For example, if ascertainment 105 shows that the detected object is notreal, i.e., is unreal, it is provided, for example, that one or more ofthe above-described actions is/are controlled.

A detected elevated object may be classified as follows, for example:motor vehicle, pedestrian, cyclist, animal, baby stroller, other.

FIG. 2 shows a system 201 for detecting an elevated object situatedwithin a parking facility. System 201 is designed for executing orcarrying out the method for detecting an elevated object situated withina parking facility.

System 201 encompasses, for example:

-   -   at least two video cameras 203 that are spatially distributed        within the parking facility and whose visual ranges overlap in        an overlap area in order to record a particular video image of        the overlap area, and    -   a data processing device 205 that is designed for carrying out        one or more of the following steps: step b), step c),        ascertaining a result of whether an elevated object has been        detected in the recorded video images, detecting an elevated        object in the recorded video images, determining whether the        detected elevated object is real, rectifying the recorded video        images, comparing the particular rectified video images to one        another to recognize a difference in the recorded overlap areas,        detecting an elevated object based on the comparison.

FIG. 3 shows a parking facility 301.

Parking facility 301 encompasses system 201 of FIG. 2.

FIG. 4 shows a first video camera 403 and a second video camera 405 thatmonitor a floor 401 of a parking facility. The two video cameras 403,405 are situated on a ceiling, for example (not shown).

First video camera 403 has a first visual range 407. Second video camera405 has a second visual range 409. The two video cameras 403, 405 aresituated in such a way that the two visual ranges 407, 409 overlap in anoverlap area 411. This overlap area 411 is part of floor 401.

Situated directly to the left of second video camera 405 is a lightsource 413 that illuminates overlap area 411 from the direction ofsecond video camera 405.

No elevated object is situated on floor 401. This means that both videocameras 403, 405 view or detect the same overlap area 411. This meansthat the two video cameras 403, 405 recognize or view the same imageinformation of overlap area 411.

The two video cameras 403, 405 each record video images of overlap area411, and the video images are rectified. If no elevated object issituated between overlap area 411 and video camera 403 and 405, theparticular rectified video images do not differ from one another, atleast not within a predefined tolerance (the predetermined tolerancevalue). In this case, no difference is recognized, so that also noelevated object is detected.

Overlap area 411 is situated, for example, on a travel area of theparking facility. This means, for example, that motor vehicles maytravel on overlap area 411.

FIG. 5 shows the two video cameras 403, 405 during the detection of anelevated object 501. Elevated object 501 has oppositely situated sides503, 505: Side 503 is referred to below as the right side (relative tothe plane of the drawing). Side 505 is referred to below as the leftside (relative to the plane of the drawing).

Elevated objects generally look different from different sides. Thismeans that elevated object 501 looks different from right side 503 thanfrom left side 505.

Elevated object 501 is situated on floor 401. Elevated object 501 issituated between overlap area 411 and the two video cameras 403, 405.

First video camera 403 detects left side 505 of elevated object 501.Second video camera 405 detects right side 503 of elevated object 501.

In this case, the particular rectified video images differ from oneanother, so that a difference may be recognized. Elevated object 501 isthen detected. In this case, the differences are greater than thepredetermined tolerance value.

In particular as the result of providing light source 413, right side503 is illuminated more intensely than left side 505. This yields thetechnical advantage, for example, that the brightnesses of the recorded,and thus also rectified, video images differ. Differences in brightnessmay be efficiently detected, so that the difference may be efficientlyrecognized so that elevated object 501 may advantageously be efficientlydetected.

Elevated object 501 is, for example, a motor vehicle that is travelingon floor 401 of the parking facility. Sides 503, 505 are, for example,front and rear sides, or the right and left sides, of the motor vehicle.

If a nonelevated, i.e., two-dimensional or flat, object is situated onfloor 401, the correspondingly rectified video images generally do notdiffer from one another within a predefined tolerance. Such atwo-dimensional object is a newspaper, a piece of paper, or leaves, forexample. The fact that in such a case, although an object, even if it isnot an elevated object, is situated on floor 401 and is possibly notdetected in the rectified video images due to the lack of a difference(differences are less than or less than or equal to the predefinedtolerance value), in this regard is not relevant here for safetyreasons, since motor vehicles may generally travel over such nonelevatedobjects. Motor vehicles may travel over leaves or paper withoutresulting in a hazardous situation or collision, in contrast to anelevated object, which may be a pedestrian, a cyclist, an animal, or amotor vehicle, for example. A motor vehicle should not collide with suchobjects.

Video images are recorded with the aid of video cameras 403, 405 andevaluated, i.e., analyzed, in order to detect an elevated object in thevideo images.

If an elevated object is detected in the recorded video images, it isprovided, for example, that video images that are recorded subsequent tothese video images with the aid of video cameras 403, 405 are similarlyanalyzed in order to verify in these subsequently recorded video imagesthe object detected in the earlier images.

If the initially detected object is not redetected in the subsequentlyrecorded video images, it is determined, for example, that the initiallydetected object is not real.

If the initially detected elevated object is detected in thesubsequently recorded video images, it is provided, for example, that anobject speed is ascertained and/or that the initially detected object aswell as the redetected object are classified.

If, for example, the ascertained object speed is greater than apredetermined object speed threshold value, it is determined that thedetected elevated object is not real.

If, for example, the two classifications differ, it is determined thatthe detected elevated object is not real.

For example, one or multiple criteria is/are provided which, when met,result in an object being detected in the video images.

One criterion, for example, is that a different rectified video imagefrom a single video camera is already sufficient, for example, to detectan elevated object, regardless of whether the other video cameras recordthe same or different video images.

Another criterion, for example, is that all video cameras must record adifferent video image in order to detect an elevated object.

Another criterion, for example, is that for n video cameras, where n isgreater than or equal to 3, m video cameras must each record a differentvideo image, where m is greater than 1 and less than n, in order todetect an elevated object, regardless of whether the other video camerasrecord the same or different video images.

The information that an object has been detected is reported ortransmitted, for example, to a parking facility management system. Theparking facility management system uses this information, for example,for planning or managing an operation of the parking facility. Theparking facility management system thus operates, for example, theparking facility based on the information.

This information is used, for example, for remote control of a motorvehicle situated within the parking facility. This means, for example,that the parking facility management system remotely controls a motorvehicle within the parking facility, based on the detected object(s).

This information is transmitted, for example, to motor vehiclesautonomously driving within the parking facility via a wirelesscommunications network.

The present invention is thus based in particular on analyzing in eachcase video images recorded in chronological succession with the aid ofvideo cameras, and when an object is detected, tracking the detectedelevated object over time to ascertain whether the detected object isreal. The video cameras are spatially distributed within a parkingfacility, which may be designed as a parking deck or as a parkinggarage, for example, in such a way that, for example, each point of atravel area is viewed or detected and/or monitored by at least two, forexample at least three, video cameras. This means that the particularvisual ranges overlap in overlap areas in each case, the overlap areascovering the travel area. The recorded video images are rectified, forexample prior to the comparison.

The corresponding rectified video images of the video cameras arecompared to one another. For example, it is provided that if all videocameras in the travel area view the same image information at a certainlocation or at a certain point, it is determined that no object issituated on the particular line of sight between the certain locationand the video cameras. In this regard, an object is not detected either.However, for example if the image information of one video camera atthis location differs from the other video cameras, it is thus clearthat an elevated object must be situated on the line of sight of thisone video camera. In this regard, an elevated object is detected.

Video images chronologically following these rectified video images areanalyzed similarly as for these earlier rectified video images, i.e., inparticular rectified and compared to one another. The result of thiscomparison is used in particular to determine whether, during detectionof an object based on the earlier video images, the detected elevatedobject in question is real.

Within the meaning of this description, the phrases “same imageinformation” and “identical image information” in particular alsoencompass the case that the pieces of image information differ maximallyby a predetermined tolerance value. Only differences that are greaterthan the predetermined tolerance value result in detection of an object.This means in particular that small differences in the brightnessinformation and/or color information are allowed in order to draw theconclusion that the pieces of image information are the same oridentical, provided that the differences are smaller than thepredetermined tolerance value.

This means in particular, for example, that a tolerance is predefined,about which the rectified video images are allowed to differ without anelevated object being detected. Only when the differences are greaterthan the predefined tolerance is an elevated object detected.

According to one specific embodiment, this means in particular that anobject is detected only when the differences in the rectified videoimages are greater than a predefined tolerance or a predeterminedtolerance value.

For example, it is provided that a motor vehicle that is drivingautonomously or by remote control moves within the parking facility onpredefined surfaces, the travel area. The video cameras are situated insuch a way, for example, that their visual ranges overlap in the travelarea. This overlap is selected in such a way that each point on theperiphery (floor, wall, for example) in the travel area is viewed ormonitored by at least three video cameras. In particular, thearrangement is selected in such a way that each point on the peripheryis viewed or monitored from a different perspective.

This means in particular that the overlap area is detected and recordedfrom different directions with the aid of the video cameras.

From each individual point of the periphery, the lines of sight to, forexample, the three video cameras that view this point may be traced. Ifmore video cameras are to be available, it is provided, for example,that of the multiple cameras, three video cameras with preferablydifferent perspectives are selected.

If no elevated object is situated on the lines of sight of the videocameras at this point, all video cameras view the same piece(s) of imageinformation (see FIG. 4), which differ maximally by a predeterminedtolerance value.

For example, if a brightness or a color of the surface of the floorchanges, for example if the floor is wet due to the introduction ofmoisture, this does not interfere with a detection of the periphery,provided that all video cameras view the same changed brightness orcolor. For example, if a two-dimensional object, such as a newspaper,piece of paper, or leaves, is situated on the floor, according to theconcept according to the present invention this nonelevated object isgenerally not detected, since all video cameras view the same piece(s)of image information that differ(s) maximally by a predeterminedtolerance value. This is not critical for safety reasons, since suchtwo-dimensional objects may be easily traveled over by motor vehicles.

If an elevated object is situated in the travel area (see FIG. 5, forexample), the lines of sight of the video cameras no longer strike theperiphery (overlap area) as expected, and instead see different views ofthe elevated object and therefore record different video images.

An elevated object is a person or a motor vehicle, for example.

For example, one video camera thus views the front side of the object,while the other video camera views the rear side of the object. The twosides generally differ significantly, and the elevated object may thusbe detected if the recorded video images are different. This effect maybe intensified, for example, by a brighter illumination of the scene,i.e., the overlap area, on one side, so that failure to notice elevatedobjects may be efficiently ruled out. Due to a different illumination ofthe various sides of an object, this object appears brighter on the moreintensely illuminated side than on the weakly illuminated side, so thatthe video cameras view different pieces of image information. Thisapplies even for monochrome objects.

The present invention (spatial distribution of the video cameras with acorresponding overlap area, illuminating the scene by way of example,and tracking a detected elevated object over time) advantageously allowsefficient determination of whether a detected elevated object isactually real, so that ultimately, elevated objects may be efficientlydetected or recognized. The concept according to the present inventionis in particular very robust against changes in brightness or changes inbrightness at specific points, for example due to solar radiation.

The information that an elevated object is detected may be transferred,for example, to a higher-order control system. This control system may,for example, stop a remote-controlled motor vehicle or transmit a stopsignal to an autonomously driving motor vehicle, so that these motorvehicles can still stop in time in front of the elevated object. Thecontrol system is encompassed by the parking facility management system,for example.

The present invention may also be advantageously used in the AVP field.“AVP” stands for “automated valet parking” and may also be referred toas “automatic parking operation.” Within the scope of such an AVPoperation, it is provided in particular that motor vehicles areautomatically parked within a parking facility, and after the end of aparking period are automatically driven from their parking position to apick-up position, at which the motor vehicle may be picked up by itsowner.

What is claimed is:
 1. A method for detecting an elevated objectsituated within a parking facility, using at least two video camerasthat are spatially distributed within the parking facility and whosevisual ranges overlap in an overlap area, the method comprising: a)recording particular video images of the overlap area using the videocameras, wherein the video images of the at least two video cameras arerecorded in chronological succession to determine whether or not adetected elevated object is real; b) analyzing the recorded video imagesto detect the elevated object in the recorded video images; and c)ascertaining, based on the recorded video images, whether in thedetection of the elevated object the detected elevated object is real,and at which location in the video images, the detected elevated objectmoves into the particular video image and/or moves out of the particularvideo image, wherein it is determined that the detected elevated objectis real when the detected object moves into the particular video imageat an edge of the video image, and/or moves out of the particular videoimage at the edge of the video image, and it is determined that thedetected elevated object is not real when the detected object appearswithin the video image or disappears within the video image withouthaving crossed the edge of the video image; wherein for detecting theelevated object in the recorded video images, the following steps areprovided according to the analysis according to step b): rectifying therecorded video images by at least transforming the recorded video imagesinto a bird's-eye view; comparing the particular rectified video imagesto one another in order to recognize a difference in the recordedoverlap areas; and detecting the elevated object based on thecomparison.
 2. The method as recited in claim 1, wherein step c)includes ascertaining an object speed, the ascertained object speedbeing compared to a predetermined object speed threshold value, andbased on the comparison, determining whether the detected elevatedobject is real.
 3. The method as recited in claim 1, wherein step c)includes ascertaining a movement of the detected elevated object, itbeing ascertained whether the movement of the detected elevated objectis plausible, and based on the plausibility check, determining whetherthe detected elevated object is real.
 4. The method as recited in claim3, wherein it is ascertained whether the ascertained movement isplausible for the classified object.
 5. The method as recited in claim1, wherein step c) includes classifying the detected elevated object, itbeing determined, based on the classification, whether the detectedelevated object is real.
 6. The method as recited in claim 5, whereinstep c) includes ascertaining an object speed, the ascertained objectspeed being compared to a predetermined object speed threshold value,and based on the comparison, determining whether the detected elevatedobject is real, and wherein based on the classification, anobject-specific speed threshold value is predefined as the predeterminedobject speed threshold value for the comparison.
 7. The method asrecited in claim 1, wherein when the detected elevated object is notreal, one or more of the following actions is/are controlled: stoppingall driverless motor vehicles traveling within the parking facility,summoning a service person to the video cameras, carrying out a functioncheck of the video cameras, adjusting a particular setpoint trajectoryto be driven along by driverless motor vehicles traveling within theparking facility to bypass a section of the parking facility thatencompasses the overlap area, blocking a section of the parking facilitythat encompasses the overlap area, blocking a story of the parkingfacility that encompasses the overlap area, transmitting an errormessage to an operator via a communications network.
 8. The method asrecited in claim 1, wherein the overlap area encompasses a travel areafor motor vehicles.
 9. A system for detecting an elevated objectsituated within a parking facility, the system including at least twovideo cameras that are spatially distributed within the parking facilityand whose visual ranges overlap in an overlap area, the systemconfigured to: a) record particular video images of the overlap areausing the video cameras, wherein the video images of the at least twovideo cameras are recorded in chronological succession to determinewhether or not a detected elevated object is real; b) analyze therecorded video images to detect the elevated object in the recordedvideo images; and c) ascertain, based on the recorded video images,whether in the detection of an elevated object the detected elevatedobject is real, and at which location in the video images, the detectedelevated object moves into the particular video image and/or moves outof the particular video image, wherein it is determined that thedetected elevated object is real when the detected object moves into theparticular video image at an edge of the video image, and/or moves outof the particular video image at the edge of the video image, and it isdetermined that the detected elevated object is not real when thedetected object appears within the video image or disappears within thevideo image without having crossed the edge of the video image; whereinfor detecting the elevated object in the recorded video images, thefollowing steps are provided according to the analysis according to stepb): rectifying the recorded video images by at least transforming therecorded video images into a bird's-eye view; comparing the particularrectified video images to one another in order to recognize a differencein the recorded overlap areas; and detecting the elevated object basedon the comparison.
 10. A parking facility that includes a system fordetecting an elevated object situated within the parking facility, thesystem including at least two video cameras that are spatiallydistributed within the parking facility and whose visual ranges overlapin an overlap area, the system configured to: a) record particular videoimages of the overlap area using the video cameras, wherein the videoimages of the at least two video cameras are recorded in chronologicalsuccession to determine whether or not a detected elevated object isreal; b) analyze the recorded video images to detect the elevated objectin the recorded video images; and c) ascertain, based on the recordedvideo images, whether in the detection of the elevated object thedetected elevated object is real, and at which location in the videoimages, the detected elevated object moves into the particular videoimage and/or moves out of the particular video image, wherein it isdetermined that the detected elevated object is real when the detectedobject moves into the particular video image at an edge of the videoimage, and/or moves out of the particular video image at the edge of thevideo image, and it is determined that the detected elevated object isnot real when the detected object appears within the video image ordisappears within the video image without having crossed the edge of thevideo image; wherein for detecting the elevated object in the recordedvideo images, the following steps are provided according to the analysisaccording to step b): rectifying the recorded video images by at leasttransforming the recorded video images into a bird's-eye view; comparingthe particular rectified video images to one another in order torecognize a difference in the recorded overlap areas; and detecting theelevated object based on the comparison.
 11. A non-transitory computerreadable storage medium on which is stored a computer program thatincludes program code for detecting an elevated object situated within aparking facility, using at least two video cameras that are spatiallydistributed within the parking facility and whose visual ranges overlapin an overlap area, the computer program, when executed by a computer,causing the computer to perform: a) recording particular video images ofthe overlap area using the video cameras, wherein the video images ofthe at least two video cameras are recorded in chronological successionto determine whether or not a detected elevated object is real; b)analyzing the recorded video images to detect the elevated object in therecorded video images; and c) ascertaining, based on the recorded videoimages, whether in the detection of the elevated object the detectedelevated object is real, and at which location in the video images, thedetected elevated object moves into the particular video image and/ormoves out of the particular video image, wherein it is determined thatthe detected elevated object is real when the detected object moves intothe particular video image at an edge of the video image, and/or movesout of the particular video image at the edge of the video image, and itis determined that the detected elevated object is not real when thedetected object appears within the video image or disappears within thevideo image without having crossed the edge of the video image; whereinfor detecting the elevated object in the recorded video images, thefollowing steps are provided according to the analysis according to stepb): rectifying the recorded video images by at least transforming therecorded video images into a bird's-eye view; comparing the particularrectified video images to one another in order to recognize a differencein the recorded overlap areas; and detecting the elevated object basedon the comparison.